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Homework Help: Matrix problem

  1. Feb 25, 2010 #1
    Given the matrix
    A= [a 1 9]
    [a -6 3]
    [5 -8 a]

    find all values of a that makes 4a602ec89d76de74a9e73df5c71e221.png
    give your answers in increasing order.
    a can be _ & _

    NEED HELP! IM BEYOND STUCK! I have no idea to even approach this problem! Thanks!
     
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Feb 25, 2010 #2
    I don't understand why you are stuck.
    You don't know how to calculate determinants or solve equations?
     
  4. Feb 25, 2010 #3
    I don't know how to solve the equation
     
  5. Feb 25, 2010 #4
    [tex]\[
    \left| {\left. {\bf{A}} \right|} \right. = 285 - 48a - 7a^2 = 0
    \]
    [/tex]
    You can't solve that?
     
  6. Feb 25, 2010 #5
    oh, now I feel dumb. Thanks for the help!
     
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